On Sun, Jul 21, 2019 at 5:55 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> The FROM case could be improved perhaps, if somebody wanted to put
> time into it. You'd still need to be prepared to build a tuplestore,
> in case of rescan or backwards fetch; but in principle you could return
> rows immediately while stashing them aside in a tuplestore.
But you could skip it if you could prove that no rescans or backward
fetches are possible for a particular node, something that we also
want for Gather, as discussed not long ago.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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